/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.confignode.procedure.impl.statemachine;

import org.apache.iotdb.common.rpc.thrift.TConsensusGroupId;
import org.apache.iotdb.common.rpc.thrift.TDataNodeLocation;
import org.apache.iotdb.common.rpc.thrift.TSStatus;
import org.apache.iotdb.commons.exception.runtime.ThriftSerDeException;
import org.apache.iotdb.commons.utils.ThriftCommonsSerDeUtils;
import org.apache.iotdb.confignode.procedure.env.ConfigNodeProcedureEnv;
import org.apache.iotdb.confignode.procedure.env.DataNodeRemoveHandler;
import org.apache.iotdb.confignode.procedure.exception.ProcedureException;
import org.apache.iotdb.confignode.procedure.state.ProcedureLockState;
import org.apache.iotdb.confignode.procedure.state.RegionTransitionState;
import org.apache.iotdb.confignode.procedure.store.ProcedureType;
import org.apache.iotdb.confignode.rpc.thrift.TRegionMigrateResultReportReq;
import org.apache.iotdb.rpc.TSStatusCode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;

import static org.apache.iotdb.confignode.conf.ConfigNodeConstant.REMOVE_DATANODE_PROCESS;
import static org.apache.iotdb.confignode.procedure.env.DataNodeRemoveHandler.getIdWithRpcEndpoint;
import static org.apache.iotdb.rpc.TSStatusCode.SUCCESS_STATUS;

/**
 * Region migrate procedure
 */
public class RegionMigrateProcedure
        extends StateMachineProcedure<ConfigNodeProcedureEnv, RegionTransitionState> {
    private static final Logger LOG = LoggerFactory.getLogger(RegionMigrateProcedure.class);
    private static final int RETRY_THRESHOLD = 5;

    /**
     * Wait region migrate finished
     */
    private final Object regionMigrateLock = new Object();

    private TConsensusGroupId consensusGroupId;

    private TDataNodeLocation originalDataNode;

    private TDataNodeLocation destDataNode;

    private boolean migrateSuccess = true;

    private String migrateResult = "";

    public RegionMigrateProcedure() {
        super();
    }

    public RegionMigrateProcedure(
            TConsensusGroupId consensusGroupId,
            TDataNodeLocation originalDataNode,
            TDataNodeLocation destDataNode) {
        super();
        this.consensusGroupId = consensusGroupId;
        this.originalDataNode = originalDataNode;
        this.destDataNode = destDataNode;
    }

    @Override
    protected Flow executeFromState(ConfigNodeProcedureEnv env, RegionTransitionState state) {
        if (consensusGroupId == null) {
            return Flow.NO_MORE_STATE;
        }
        TSStatus tsStatus;
        DataNodeRemoveHandler handler = env.getDataNodeRemoveHandler();
        try {
            switch (state) {
                case REGION_MIGRATE_PREPARE:
                    setNextState(RegionTransitionState.CREATE_NEW_REGION_PEER);
                    break;
                case CREATE_NEW_REGION_PEER:
                    handler.createNewRegionPeer(consensusGroupId, destDataNode);
                    setNextState(RegionTransitionState.ADD_REGION_PEER);
                    break;
                case ADD_REGION_PEER:
                    tsStatus = handler.addRegionPeer(destDataNode, consensusGroupId);
                    if (tsStatus.getCode() == SUCCESS_STATUS.getStatusCode()) {
                        waitForOneMigrationStepFinished(consensusGroupId, state);
                    } else {
                        throw new ProcedureException("ADD_REGION_PEER executed failed in DataNode");
                    }
                    setNextState(RegionTransitionState.CHANGE_REGION_LEADER);
                    break;
                case CHANGE_REGION_LEADER:
                    handler.changeRegionLeader(consensusGroupId, originalDataNode, destDataNode);
                    setNextState(RegionTransitionState.REMOVE_REGION_PEER);
                    break;
                case REMOVE_REGION_PEER:
                    tsStatus = handler.removeRegionPeer(originalDataNode, destDataNode, consensusGroupId);
                    if (tsStatus.getCode() == SUCCESS_STATUS.getStatusCode()) {
                        waitForOneMigrationStepFinished(consensusGroupId, state);
                    } else {
                        throw new ProcedureException("REMOVE_REGION_PEER executed failed in DataNode");
                    }
                    setNextState(RegionTransitionState.DELETE_OLD_REGION_PEER);
                    break;
                case DELETE_OLD_REGION_PEER:
                    tsStatus = handler.deleteOldRegionPeer(originalDataNode, consensusGroupId);
                    if (tsStatus.getCode() == SUCCESS_STATUS.getStatusCode()) {
                        waitForOneMigrationStepFinished(consensusGroupId, state);
                    }
                    // Remove consensus group after a node stop, which will be failed, but we will
                    // continuously execute.
                    setNextState(RegionTransitionState.UPDATE_REGION_LOCATION_CACHE);
                    break;
                case UPDATE_REGION_LOCATION_CACHE:
                    handler.updateRegionLocationCache(consensusGroupId, originalDataNode, destDataNode);
                    return Flow.NO_MORE_STATE;
            }
        } catch (Exception e) {
            LOG.error(
                    "{}, Meets error in region migrate state, "
                            + "please do the rollback operation yourself manually according to the error message!!! "
                            + "error state: {}, migrateResult: {}",
                    REMOVE_DATANODE_PROCESS,
                    state,
                    migrateResult);
            if (isRollbackSupported(state)) {
                setFailure(new ProcedureException("Region migrate failed at state: " + state));
            } else {
                LOG.error(
                        "{}, Failed state [{}] is not support rollback, originalDataNode: {}",
                        REMOVE_DATANODE_PROCESS,
                        state,
                        getIdWithRpcEndpoint(originalDataNode));
                if (getCycles() > RETRY_THRESHOLD) {
                    setFailure(
                            new ProcedureException(
                                    "Procedure retried failed exceed 5 times, state stuck at " + state));
                }

                // meets exception in region migrate process terminate the process
                return Flow.NO_MORE_STATE;
            }
        }
        return Flow.HAS_MORE_STATE;
    }

    @Override
    protected void rollbackState(ConfigNodeProcedureEnv env, RegionTransitionState state)
            throws IOException, InterruptedException, ProcedureException {
    }

    @Override
    protected boolean isRollbackSupported(RegionTransitionState state) {
        return false;
    }

    @Override
    protected ProcedureLockState acquireLock(ConfigNodeProcedureEnv configNodeProcedureEnv) {
        configNodeProcedureEnv.getSchedulerLock().lock();
        try {
            if (configNodeProcedureEnv.getRegionMigrateLock().tryLock(this)) {
                LOG.info("procedureId {} acquire lock.", getProcId());
                return ProcedureLockState.LOCK_ACQUIRED;
            }
            configNodeProcedureEnv.getRegionMigrateLock().waitProcedure(this);

            LOG.info("procedureId {} wait for lock.", getProcId());
            return ProcedureLockState.LOCK_EVENT_WAIT;
        } finally {
            configNodeProcedureEnv.getSchedulerLock().unlock();
        }
    }

    @Override
    protected void releaseLock(ConfigNodeProcedureEnv configNodeProcedureEnv) {
        configNodeProcedureEnv.getSchedulerLock().lock();
        try {
            LOG.info("procedureId {} release lock.", getProcId());
            if (configNodeProcedureEnv.getRegionMigrateLock().releaseLock(this)) {
                configNodeProcedureEnv
                        .getRegionMigrateLock()
                        .wakeWaitingProcedures(configNodeProcedureEnv.getScheduler());
            }
        } finally {
            configNodeProcedureEnv.getSchedulerLock().unlock();
        }
    }

    @Override
    protected RegionTransitionState getState(int stateId) {
        return RegionTransitionState.values()[stateId];
    }

    @Override
    protected int getStateId(RegionTransitionState regionTransitionState) {
        return regionTransitionState.ordinal();
    }

    @Override
    protected RegionTransitionState getInitialState() {
        return RegionTransitionState.REGION_MIGRATE_PREPARE;
    }

    @Override
    public void serialize(DataOutputStream stream) throws IOException {
        stream.writeShort(ProcedureType.REGION_MIGRATE_PROCEDURE.getTypeCode());
        super.serialize(stream);
        ThriftCommonsSerDeUtils.serializeTDataNodeLocation(originalDataNode, stream);
        ThriftCommonsSerDeUtils.serializeTDataNodeLocation(destDataNode, stream);
        ThriftCommonsSerDeUtils.serializeTConsensusGroupId(consensusGroupId, stream);
    }

    @Override
    public void deserialize(ByteBuffer byteBuffer) {
        super.deserialize(byteBuffer);
        try {
            originalDataNode = ThriftCommonsSerDeUtils.deserializeTDataNodeLocation(byteBuffer);
            destDataNode = ThriftCommonsSerDeUtils.deserializeTDataNodeLocation(byteBuffer);
            consensusGroupId = ThriftCommonsSerDeUtils.deserializeTConsensusGroupId(byteBuffer);
        } catch (ThriftSerDeException e) {
            LOG.error("Error in deserialize RemoveConfigNodeProcedure", e);
        }
    }

    @Override
    public boolean equals(Object that) {
        if (that instanceof RegionMigrateProcedure) {
            RegionMigrateProcedure thatProc = (RegionMigrateProcedure) that;
            return thatProc.getProcId() == this.getProcId()
                    && thatProc.getState() == this.getState()
                    && thatProc.originalDataNode.equals(this.originalDataNode)
                    && thatProc.destDataNode.equals(this.destDataNode)
                    && thatProc.consensusGroupId.equals(this.consensusGroupId);
        }
        return false;
    }

    public TSStatus waitForOneMigrationStepFinished(
            TConsensusGroupId consensusGroupId, RegionTransitionState state) throws Exception {

        LOG.info(
                "{}, Wait for state {} finished, regionId: {}",
                REMOVE_DATANODE_PROCESS,
                state,
                consensusGroupId);

        TSStatus status = new TSStatus(SUCCESS_STATUS.getStatusCode());
        synchronized (regionMigrateLock) {
            try {
                // TODO set timeOut?
                regionMigrateLock.wait();

                if (!migrateSuccess) {
                    throw new ProcedureException(
                            String.format("Region migration failed, regionId: %s", consensusGroupId));
                }
            } catch (InterruptedException e) {
                LOG.error(
                        "{}, region migration {} interrupt", REMOVE_DATANODE_PROCESS, consensusGroupId, e);
                Thread.currentThread().interrupt();
                status.setCode(TSStatusCode.MIGRATE_REGION_ERROR.getStatusCode());
                status.setMessage("Waiting for region migration interruption," + e.getMessage());
            }
        }
        return status;
    }

    /**
     * DataNode report region migrate result to ConfigNode, and continue
     */
    public void notifyTheRegionMigrateFinished(TRegionMigrateResultReportReq req) {

        LOG.info(
                "{}, ConfigNode received region migration result reported by DataNode: {}",
                REMOVE_DATANODE_PROCESS,
                req);

        // TODO the req is used in roll back
        synchronized (regionMigrateLock) {
            TSStatus migrateStatus = req.getMigrateResult();
            // Migration failed
            if (migrateStatus.getCode() != SUCCESS_STATUS.getStatusCode()) {
                LOG.info(
                        "{}, Region migration failed in DataNode, migrateStatus: {}",
                        REMOVE_DATANODE_PROCESS,
                        migrateStatus);
                migrateSuccess = false;
                migrateResult = migrateStatus.toString();
            }
            regionMigrateLock.notify();
        }
    }

    public TConsensusGroupId getConsensusGroupId() {
        return consensusGroupId;
    }
}
